1. Field of the Invention
The invention relates to a signal strength adapter circuit for smoothly changing a signal strength starting with an initial signal strength and ending with a final signal strength, the circuit comprising a signal adapter having a signal input for receiving the signal, a digital set input for receiving a strength value, and a signal output for presenting an adapted signal that has a strength corresponding to the strength value on the set input, and the circuit further including control means for generating, at successive discrete instants, a series of strength values which fix a function changing with time and including means for applying the generated strength values to the set input.
2. Description of the Related Art
A circuit of said type which is also denoted as of fade-in and fade-out circuit, is known, for example, from U.S. Pat. No. 4,306,114.
In the circuit described in that document, the signal strength of an audio signal is adapted in fading steps. The step size in absolute sense is the same for each adaptation, so that the variation with time of the signal strength presents an approximately linear pattern. Such a linear variation of the strength is sensed as not being smooth by the listener. In addition, the steps are selected to be rather large which is experienced by most listeners as annoying. Finally, the possibilities to set the speed with which an adaptation is carried out and the extent of the adaptation are limited.